Staging Laparoscopy for Hilar Cholangiocarcinoma: Is it Still Worthwhile?

This study was designed to evaluate the benefit of staging laparoscopy (SL) in patients with suspected hilar cholangiocarcinoma (HCCA) during the past 10 years. Only 50-60% of patients with HCCA who undergo laparotomy are ultimately amenable to a potentially curative resection. In a previous study, we recommended routine use of SL to prevent unnecessary laparotomies. The accuracy of imaging techniques, however, has significantly improved during the past decade, which is likely to impact the yield and accuracy of SL. From 2000 to 2010, 195 patients with suspected HCCA were analyzed. The yield and accuracy of SL were calculated by dividing total number of avoided laparotomies by the total number of laparoscopies or by all patients with unresectable disease, respectively. Factors associated with better yield and accuracy were assessed. Of 195 patients with HCCA, 175 underwent SL. The yield of SL was 14% and the accuracy was 32%. Operative morbidity of SL was 3%, and operative morbidity of laparotomy for unresectable disease was 33%. No clear factors that influenced the yield of SL were found. Overall yield and accuracy of SL for HCCA in the present series decreased to 14% and 32%, respectively, compared with earlier reports. This finding is likely the result of improved imaging techniques that evolved during the past decade. The place of SL in the workup of patients with HCCA needs to be reconsidered, and one should decide whether the declining additional value of SL still outweighs the drawbacks of S

Application profiling and resource management for MapReduce

Scale of data generated and processed is exponential growth in the Big Data ear. It poses a challenge that is far beyond the goal of a single computing system. Processing such vast amount of data on a single machine is impracticable in term of time or cost. Hence, distributed systems, which can harness very large clusters of commodity computers and processing data within restrictive time deadlines, are imperative. In this thesis, we target two aspects of distributed systems: application profiling and resource management. We study a MapReduce system in detail, which is a programming paradigm for large scale distributed computing, and presents solutions to tackle three key problems. Firstly, this thesis analyzes the characteristics of jobs running on the MapReduce system to reveal the problem—the Application scope of MapReduce has been extended beyond the original design goal that was large-scale data processing. This problem enables us to present a Workload Characteristic Oriented Scheduler (WCO), which strives for co-locating tasks of possibly different MapReduce jobs with complementing resource usage characteristics. Secondly, this thesis studies the current job priority mechanism focusing on resource management. In the MapReduce system, job priority only exists at scheduling level. High priority jobs are placed at the front of the scheduling queue and dispatched first. Resource, however, is fairly shared among jobs running at the same worker node without any consideration for their priorities. In order to resolve this, this thesis presents a non-intrusive slot layering solution, which dynamically allocates resource between running jobs based on their priority and efficiently reduces the execution time of high priority jobs while improves overall throughput. Last, based on the fact of underutilization of resource at each individual worker node, this thesis propose a new way, Local Resource Shaper (LRS), to smooth resource consumption of each individual job by automatically tuning the execution of concurrent jobs to maximize resource utilization while minimizing resource contention

Surgical Treatment of Renal Cell Cancer Liver Metastases: A Population-Based Study

Background: To evaluate outcomes of surgical treatment in patients with hepatic metastases from renal-cell carcinoma in the Netherlands, and to identify prognostic factors for survival after resection. Renal-cell carcinoma has an incidence of 2,000 new patients in the Netherlands each year (12.5/100,000 inhabitants). According to literature, half of these patients ultimately develop distant metastases with 20% involvement of the liver. Resection of renal-cell carcinoma liver metastases (RCCLM) is performed in only a minority of patients. Hence, little is known about outcome of resectable RCCLM. Methods: Patients were retrieved from local databases of theNetherlands Task Force for Liver Surgery (14 centers) and from the Dutch collective pathology database. Survival and prognostic factors were determined by Kaplan-Meier analysis and log rank test. Results: Thirty-three patients were identified who underwent resection (n = 29) or local ablation (n = 4) of RCCLM in the Netherlands between 1990 and 2008. These patients comprise 0.5% to 1% of the total population of patients diagnosed with RCCLM in that period. There was no operative mortality. The overall survival at 1, 3, and 5 years was 79, 47, and 43%, respectively. Metachronous metastases (n = 23, P = 0.03) and radical resection (n = 19, P < 0.001) were statistically significant prognosticators of ov

Influence of socioeconomic factors on pregnancy outcome in women with structural heart disease

OBJECTIVE: Cardiac disease is the leading cause of indirect maternal mortality. The aim of this study was to analyse to what extent socioeconomic factors influence the outcome of pregnancy in women with heart disease.  METHODS: The Registry of Pregnancy and Cardiac disease is a global prospective registry. For this analysis, countries that enrolled ≥10 patients were included. A combined cardiac endpoint included maternal cardiac death, arrhythmia requiring treatment, heart failure, thromboembolic event, aortic dissection, endocarditis, acute coronary syndrome, hospitalisation for cardiac reason or intervention. Associations between patient characteristics, country characteristics (income inequality expressed as Gini coefficient, health expenditure, schooling, gross domestic product, birth rate and hospital beds) and cardiac endpoints were checked in a three-level model (patient-centre-country).  RESULTS: A total of 30 countries enrolled 2924 patients from 89 centres. At least one endpoint occurred in 645 women (22.1%). Maternal age, New York Heart Association classification and modified WHO risk classification were associated with the combined endpoint and explained 37% of variance in outcome. Gini coefficient and country-specific birth rate explained an additional 4%. There were large differences between the individual countries, but the need for multilevel modelling to account for these differences disappeared after adjustment for patient characteristics, Gini and country-specific birth rate.  CONCLUSION: While there are definite interregional differences in pregnancy outcome in women with cardiac disease, these differences seem to be mainly driven by individual patient characteristics. Adjustment for country characteristics refined the results to a limited extent, but maternal condition seems to be the main determinant of outcome

Prognostic impact of preoperative imaging parameters on resectability of hilar cholangiocarcinoma

Objectives. To evaluate, in hilar cholangiocarcinoma (HCCA), the prognostic impact of specific preoperative radiologic parameters on resectability, metastases, and yield of laparoscopy, and to evaluate the currently used staging systems. Methods. Consecutive patients with HCCA presenting in our center from January 2003 through August 2010 were evaluated. Suspicion on lymph node metastasis, portal vein and hepatic artery involvement, lobar atrophy, and proximal extent of ductal invasion was scored. The prognostic value of these parameters for predicting resectability, yield of diagnostic laparoscopy, likelihood of metastatic disease, R0 resection, and survival was assessed. The Bismuth-Corlette classification and MSKCC staging system were evaluated. Results. Of all 289 evaluated patients, 158 patients (55%) had unresectable disease based on cross-sectional imaging studies or diagnostic laparoscopy; 131 patients (45%) underwent exploration. 83 patients (64%) underwent resection, of whom 67 (87%) had a radical (R0) resection. Suspicious lymph nodes and involvement of the hepatic artery were important prognostic factors for resectability. Predictive power of the evaluated staging systems was limited. Conclusions. Current staging systems predict resectability, but there is room for improvement. Hepatic artery involvement and nodal status might be important factors for prediction of resectability and should be considered in future staging system

A nationwide survey on the perceptions of general surgeons on artificial intelligence

Aim: Artificial intelligence (AI) has the potential to improve perioperative diagnosis and decision making. Despite promising study results, the majority of AI platforms in surgery currently remain in the research setting. Understanding the current knowledge and general attitude of surgeons toward AI applications in their surgical practice is essential and can contribute to the future development and uptake of AI in surgery.Methods: In March 2021, a web-based survey was conducted among members of the Dutch Association of Surgery. The survey measured opinions on the existing knowledge, expectations, and concerns on AI among surgical residents and surgeons.Results: A total of 313 respondents completed the survey. Overall, 85% of the respondents agreed that AI could be of value in the surgical field and 61% expected AI to improve their diagnostic ability. The outpatient clinic (35.8%) and operating room (39.6%) were stated as area of interest for the use of AI. Statistically, surgeons working in an academic hospital were more likely to be aware of the possibilities of AI (P = 0.01). The surgeons in this survey were not worried about job replacement, however they raised the greatest concerns on accountability issues (50.5%), loss of autonomy (46.6%), and risk of bias (43.5%).Conclusion: This survey demonstrates that the majority of the surgeons show a positive and open attitude towards AI. Although various ethical issues and concerns arise, the expectations regarding the implementation of future surgical AI applications are high

Extent of liver resection for hilar cholangiocarcinoma (Klatskin tumor): how much is enough?

Hilar resection in combination with extended liver resections has resulted in a higher rate of R0 resections and increased survival in patients with hilar cholangiocarcinoma (HCCA). This aggressive surgical approach is, however, associated with high rates of operative morbidity and mortality, largely due to postresectional liver failure. We previously reported a series after resection of HCCA in which R0 resection rate was 59% with a mortality rate of 10%. In this study, we assessed mortality of extended liver resections after optimizing liver functional reserve and application of parenchyma-sparing techniques. From 2008 until June 2010, 41 consecutive patients underwent resection on the suspicion of HCCA. Preoperative workup included staging laparoscopy, preoperative biliary drainage, assessment of volume/function of future remnant liver and radiation therapy to prevent seeding metastases. Modified right and left extended hemihepatectomies were performed preserving parts of segments 4 and 8, respectively, while pursuing complete excision of the tumor. Outcomes of resection were evaluated. The majority of resections (78%) were performed for Bismuth type III-IV tumors. Preoperative biliary drainage was undertaken in 37 (90%) patients. Hilar resection in combination with liver resection was performed in 35 (85%) patients. Of these resections, 61% were modified extended resections including central liver resections. The R0 resection rate was 92%. Postoperative morbidity and mortality rates were 54 and 7%, respectively. Strategies to optimize liver function and to reduce removal of functional liver parenchyma were associated with a decrease in mortality (7%) while undertaking extended resection for HCCA with an R0 resection rate of 92

Differences in immunohistochemical biomarkers between intra- and extrahepatic cholangiocarcinoma: a systematic review and meta-analysis

Cholangiocarcinomas of different locations differ in growth patterns, symptoms, treatment response, and survival. Still, they are regarded in many studies as a uniform malignancy. Because intra- (iCCA) and extrahepatic (eCCA) cholangiocarcinoma display such differences, we performed a systematic review and meta-analysis to analyze differences in the immunohistochemical profile of these tumors. In February 2014, we searched the two main medical literature databases MEDLINE and EMBASE. We extracted risk ratios and 95% confidence intervals from the identified studies and performed random-effects model meta-analyses in accordance with PRISMA and REMARK guidelines. A total of 54 cohort studies, including 4458 patients and studying 102 individual markers met the inclusion criteria. Of the 57 markers that were evaluated in more than 30 iCCA and eCCA patients, 18 showed a statistically significant difference in expression between iCCA and eCCA. Biomarkers expressed differently between iCCA and eCCA included potential targets of therapy: EGFR, c-erbB-2 and VEGF-A. Several markers showed no statistical difference but large 95% confidence intervals, suggesting insufficient sample size. This systematic review shows differences in marker expression between iCCA and eCCA. Consequently, patients with iCCA and eCCA may benefit from different treatment strategie

Diagnostic accuracy of staging laparoscopy for detecting metastasized or locally advanced perihilar cholangiocarcinoma: a systematic review and meta-analysis

Despite extensive preoperative staging, still almost half of patients with potentially resectable perihilar cholangiocarcinoma (PHC) have locally advanced or metastasized disease upon exploratory laparotomy. The value of routine staging laparoscopy (SL) in these patients remains unclear with varying results reported in the literature. The aim of the present systematic review was to provide an overview of studies on SL in PHC and to define its current role in preoperative staging. A systematic review and meta-analysis were performed in PubMed and EMBASE regarding studies providing data on the diagnostic accuracy of SL in PHC. Primary outcome measures were the overall yield and sensitivity to detect unresectable disease. Secondary outcomes were the yield and sensitivity for recent studies (after 2010) and large study cohorts (≥100 patients) and specific (metastatic) lesions. Methodological quality of studies was assessed with the Quality Assessment of Diagnostic Accuracy Studies tool. From 173 records, 12 studies including 832 patients met the inclusion criteria. The yield of SL in PHC varied from 6.4 to 45.0 % with a pooled yield of 24.4 % [95 % confidence interval (CI) 16.4-33.4]. Sensitivity to detect unresectable disease ranged from 31.6 to 75 % with a pooled sensitivity of 52.2 % (95 % CI 47.1-57.2). Sensitivity was highest for peritoneal metastases (80.7 %, 95 % CI 70.9-88.3). Subgroup analysis revealed that the yield and sensitivity tended to be lower for studies after 2010. Considerable heterogeneity was detected among the studies. The results of the pooled analyses suggest that one in four patients with potentially resectable PHC benefits from SL. Given considerable heterogeneity, a trend to lower yield in more recent studies and further improvement of preoperative imaging over time, the routine use of SL seems discouraging. Studies that identify predictors of unresectability, that enable selection of patients who will benefit the most from this procedure, are neede